Despite the fact that most convincing arguments for the importance of soluble receptors in the expression of steroid hormone action originate from studies of androgen resistance syndromes, detailed information on receptor structure and function is based on work with other steroid receptors. Although several androgen-regulated genes have been studied in great detail, androgen receptor has not yet been purified extensively enough to permit raising of receptor antibodies. Moreover, cloning of androgen receptor gene has not been accomplished. The specific aims of this proposal are: (1) Isolate and purify the human androgen receptor from prostatic tissue and cultured MCF-7 cells (a human breast cancer cell line). (2) Raise monoclonal and polyclonal androgen receptor antibodies. (3) Prepare cDNA clones for the human androgen receptor-mRNA. To achieve this goal, antibodies will be used to purify receptor-mRNA and screen cDNA libraries for receptor-cDNA sequences. An alternative cloning approach will be the use of human/mouse cell hybrids with and without the human androgen receptor locus. The receptor-cDNAs will be sequenced to permit deduction of the primary amino acid sequence of this protein. (4) Isolate the gene(s) encoding the androgen receptor from a human DNA library with cloned cDNAs and characterize the structure of the gene. (5) Perform studies on the properties of the receptor protein as well as the structure and expression of the receptor gene in various human diseases, such as androgen resistance syndromes, benign prostatic hyperplasia, and prostatic cancer. These latter studies are aimed at answering the following important questions: first, what are the structural features of the androgen receptor and its gene that are responsible for androgen resistance syndromes? Second, what is the subcellular localization of the androgen receptor in prostatic tissue? (In particular, is there a difference between normal and diseased prostate?) Third, are the receptor and its mRNA evenly distributed among the various cell types of the human prostate? The long-term goals are to elucidate the structure of the human androgen receptor and to characterize the gene coding for this protein. Achievement of these goals would be a major step in furthering our understanding of androgen action as it relates to basic mechanisms and/or clinical medicine.